A conventional pre-processing buffer and Reed-Solomon use a common RAM to handle corrupted data. Such an arrangement and processing is for example used to correct data stored on an optical information media like a DVD for reproduction purposes. It is desirable to avoid to feed corrupted data to the Reed-Solomon decoder or to use a RAM to store the ECC block or to read defect parts several times what decreases the speed of the data path. DVD is an acronym for Digital Versatile Disc and ECC is an acronym for Error Correction Code—an electronic method of checking the integrity of data.
The data of the ECC is hierarchically organized in pieces of the data stream. The highest unit is an ECC-block that is divided into a number of sectors. Each sector is built up by a number of rows with a fixed length. To enable a correction of the stream a number of parity bytes are appended to each row; the number of the additional bytes determines the number of correctable faults per row. In addition to this facility of horizontal correction the same calculation is performed vertically over all bytes of an ECC-block which are at the same position of a row: the result is organized in additional rows of the ECC-block.
To control the order of sectors the first bytes contain identification information. The blocks in front of the buffer and Reed-Solomon part get the stream in frames two of which building a row: an identification of the frame order is evaluated and the result made available to the buffer by appropriate sync-signals.
A conventional arrangement stores the data into the common RAM with respect of the identification control results before the Reed-Solomon decoder starts to perform the correction of corrupted data bytes. Replacing the faulty data in memory would require processing overhead that could accumulate and significantly diminish system performance.
RAM is an acronym for Random Access Memory. It is a temporary storage area that the processor uses to execute programs and to hold data. Reed Solomon is a technique term for a forward error correcting code that is used to offset the effects of bit error in the receiving bit stream. Reed-Solomon codes are special and widely implemented because they are almost perfect in the sense that the extra redundant data added on by the encoder is at a minimum for any level of error correction so that no bits are wasted.
A Reed-Solomon decoder chip containing two frame buffer controllers that interface with two off-chip buffers, one of which is serving the incoming data has already been disclosed by IEEE International Solid-State Circuit Conference, US, IEEE Inc. (February 1998) XP862225.